Add a test for FEInterfaceValues::reinit with no dominating FE.

diff --git a/tests/feinterface/fe_interface_values_13.cc b/tests/feinterface/fe_interface_values_13.cc
new file mode 100644 (file)
index 0000000..57ef0ac
--- /dev/null
+++ b/tests/feinterface/fe_interface_values_13.cc
@@ -0,0 +1,95 @@
+// ---------------------------------------------------------------------
+//
+// Copyright (C) 2023 by the deal.II authors
+//
+// This file is part of the deal.II library.
+//
+// The deal.II library is free software; you can use it, redistribute
+// it, and/or modify it under the terms of the GNU Lesser General
+// Public License as published by the Free Software Foundation; either
+// version 2.1 of the License, or (at your option) any later version.
+// The full text of the license can be found in the file LICENSE.md at
+// the top level directory of deal.II.
+//
+// ---------------------------------------------------------------------
+
+
+// Set up a two cells with different elements, such that neither element
+// dominates. Create an FEInterfaceValues object and call reinit on it.
+
+#include <deal.II/base/quadrature_lib.h>
+
+#include <deal.II/fe/fe_interface_values.h>
+#include <deal.II/fe/fe_q.h>
+#include <deal.II/fe/fe_system.h>
+
+#include <deal.II/grid/tria.h>
+
+#include "../tests.h"
+
+#include "../test_grids.h"
+
+
+template <int dim>
+void
+test()
+{
+  Triangulation<dim> tria;
+  TestGrids::hyper_line<dim>(tria, 2);
+
+  const FESystem<dim>   fe_left(FE_Q<dim>(1), FE_Q<dim>(2));
+  const QGauss<dim - 1> q_left(3);
+
+  const FESystem<dim>   fe_right(FE_Q<dim>(3), FE_Q<dim>(1));
+  const QGauss<dim - 1> q_right(4);
+
+  const hp::FECollection<dim>    fe_collection(fe_left, fe_right);
+  const hp::QCollection<dim - 1> q_collection(q_left, q_right);
+
+
+  const unsigned int face_index = 1;
+
+
+  DoFHandler<dim> dofh(tria);
+
+  auto cell     = dofh.begin();
+  auto neighbor = cell->neighbor(face_index);
+
+  cell->set_active_fe_index(0);
+  neighbor->set_active_fe_index(1);
+
+  dofh.distribute_dofs(fe_collection);
+
+
+  const UpdateFlags update_flags = update_values | update_gradients |
+                                   update_quadrature_points | update_JxW_values;
+  FEInterfaceValues<dim> fiv(fe_collection, q_collection, update_flags);
+
+  try
+    {
+      fiv.reinit(cell,
+                 face_index,
+                 numbers::invalid_unsigned_int,
+                 neighbor,
+                 cell->neighbor_of_neighbor(face_index),
+                 numbers::invalid_unsigned_int);
+    }
+  catch (ExceptionBase &exc)
+    {
+      deallog << exc.what() << std::endl;
+    }
+
+  deallog << "OK" << std::endl;
+}
+
+
+
+int
+main()
+{
+  deal_II_exceptions::disable_abort_on_exception();
+
+  initlog();
+
+  test<2>();
+}

diff --git a/tests/feinterface/fe_interface_values_13.debug.output b/tests/feinterface/fe_interface_values_13.debug.output
new file mode 100644 (file)
index 0000000..06ec85d
--- /dev/null
+++ b/tests/feinterface/fe_interface_values_13.debug.output
@@ -0,0 +1,15 @@
+
+DEAL::
+--------------------------------------------------------
+An error occurred in file <fe_interface_values.h> in function
+    void dealii::FEInterfaceValues<dim, spacedim>::reinit(const CellIteratorType&, unsigned int, unsigned int, const CellNeighborIteratorType&, unsigned int, unsigned int, unsigned int, unsigned int, unsigned int) [with CellIteratorType = dealii::TriaIterator<dealii::DoFCellAccessor<2, 2, false> >; CellNeighborIteratorType = dealii::TriaIterator<dealii::DoFCellAccessor<2, 2, false> >; int dim = 2; int spacedim = 2]
+The violated condition was: 
+    dominated_fe_index != numbers::invalid_fe_index
+Additional information: 
+    You called this function with 'q_index' left at its default value, but
+    this can only work if one of the two finite elements adjacent to this
+    face dominates the other. See the documentation of this function for
+    more information of how to deal with this situation.
+--------------------------------------------------------
+
+DEAL::OK